A:①山谷②山脊③鞍部④山顶
B:①山谷②山谷③山顶④鞍部
C:①山谷②山脊③山顶④鞍部
D:①山脊②山脊③山顶④鞍部
如图,等腰梯形ABCD中,AB∥DC,AD=BC=8,AB=10,CD=6,则梯形ABCD的面积是( ).
Last week he borrowed a book from the library. Today he has to return it to the library.
如果不动显微镜的其他部分,只是转动转换器,将物镜由10×转换成45×,视野中的光线将会____.